Chang'e I, China's first lunar orbiter, officially began exploring the moon Monday evening, the China National Space Administration (CNSA) said.

Its sensing equipment was due to become operational after the orbiter oriented its solar panel toward the sun so it can generate its own power and swung its directional antenna toward the Earth to transmit data.

The satellite is equipped with a stereo camera and interferometer, an imager and gamma/X-ray spectrometer, a laser altimeter, a microwave detector, a high-energy solar particle detector and a low-energy ion detector.

The satellite is expected to relay back its first pictures of the moon before the end of this month.

Chang'e I will not be able to relay back pictures immediately because scientists will have to take some time tweaking the equipment, Pang Zhihao, a researcher with the China Academy of Space Technology, was quoted by the Shanghai-based Oriental Morning News as saying.

By way of example, he said the aperture of the orbiter's camera will have to be adjusted to light available in space.

Factors such as the distance between the orbiter and the lunar surface will also have to be factored into the process, he said.

Pang said the images taken by Chang'e I will be wider than those snapped by Japan's lunar probe.

Those pictures were released on November 7.

The best of the images captured by Chang'e I will be released to the public before the end of this month, he said.

The satellite entered the 127-minute polar circular orbit about 200 km above the moon's surface on November 7.

It had circled the moon 135 times as of 2 pm on Sunday, CNSA spokesman Pei Zhaoyu said on Sunday.

The orbiter is under direct control for at least 15 hours a day, monitored by tracking stations in Qingdao, Shandong Province, and Kashgar, the Xinjiang Uygur Autonomous Region, as well as a station operated by the European Space Agency.

Since Chang'e I entered its present orbit, it has undergone a number of tests to determine whether it is working properly.

The satellite appears to be functioning smoothly.

Xinhua contributed to the story